In a laser treatment apparatus for performing coagulation or the like of a fundus of a patient's eye, laser beams having different wavelengths are selectively used according to a disease case and a tissue to be treated. It is therefore convenient to emit laser beams having different wavelengths by a single apparatus. Accordingly, there has been proposed a laser treatment apparatus capable of emitting laser beams having different wavelengths. For example, an apparatus having a single laser source that selectively emits three color laser beams, i.e., green, yellow, and red has been proposed (JP2002-151774A (U.S. Pat. No. 6,636,537)).
Meanwhile, the above apparatus arranged to selectively emit three color laser beams from the single laser source is more complicated in laser source configuration than an apparatus having a laser source that emits a laser beam of a single wavelength and also has a high selling price. Accordingly, in the case where some manufacturers produce an apparatus having a laser source that emits a green beam having a single wavelength and a doctor (a user) mostly conducts treatment on a disease case by using only a green laser beam, the doctor would buy the apparatus having the laser source that emits the green beam having the single wavelength. When the doctor then has to conduct treatment using a yellow laser beam in addition to the green laser beam, the doctor must additionally buy an apparatus having a laser source that emits the yellow laser beam if it is supplied by a manufacturer or an apparatus that emits three color laser beams, green, yellow, and red. If the doctor buys the latter apparatus that emits three color laser beams, this apparatus is expensive because it includes the laser source that emits an unnecessary red laser beam and also the initially bought apparatus having the laser source for the single green wavelength becomes redundant. On the other hand, if the doctor separately buys the laser apparatus for the single green laser beam and the laser apparatus for the single yellow laser beam, a total cost will be higher and an additional footprint is required.